perf tools: Fix thread comm resolution in perf sched

This reverts commit 9a92b479b2f088ee2d3194243f4c8e59b1b8c9c2 ("perf
tools: Improve thread comm resolution in perf sched") and fixes the
real bug.

The bug was elsewhere:

We are failing to resolve thread names in perf sched because the
table of threads we are building, on top of comm events, has a per
process granularity. But perf sched, unlike the other perf tools,
needs a per thread granularity as we are profiling every tasks
individually.

So fix it by building our threads table using the tid instead of
the pid as the thread identifier.

v2: Revert the previous fix - it is not really needed

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1255028657-11158-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index 25b91e784332cf46914f1cf6c6f4893f5e1d72ef..6b00529ce348981ea45d2506d42316558079a2eb 100644 (file)
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -638,7 +638,7 @@ process_comm_event(event_t *event, unsigned long offset, unsigned long head)
 {
        struct thread *thread;
 
-       thread = threads__findnew(event->comm.pid, &threads, &last_match);
+       thread = threads__findnew(event->comm.tid, &threads, &last_match);
 
        dump_printf("%p [%p]: perf_event_comm: %s:%d\n",
                (void *)(offset + head),
@@ -1034,36 +1034,6 @@ add_sched_in_event(struct work_atoms *atoms, u64 timestamp)
        atoms->nb_atoms++;
 }
 
-static struct thread *
-threads__findnew_from_ctx(u32 pid, struct trace_switch_event *switch_event)
-{
-       struct thread *th;
-
-       th = threads__findnew_nocomm(pid, &threads, &last_match);
-       if (th->comm)
-               return th;
-
-       if (pid == switch_event->prev_pid)
-               thread__set_comm(th, switch_event->prev_comm);
-       else
-               thread__set_comm(th, switch_event->next_comm);
-       return th;
-}
-
-static struct thread *
-threads__findnew_from_wakeup(struct trace_wakeup_event *wakeup_event)
-{
-       struct thread *th;
-
-       th =  threads__findnew_nocomm(wakeup_event->pid, &threads, &last_match);
-       if (th->comm)
-               return th;
-
-       thread__set_comm(th, wakeup_event->comm);
-
-       return th;
-}
-
 static void
 latency_switch_event(struct trace_switch_event *switch_event,
                     struct event *event __used,
@@ -1089,10 +1059,8 @@ latency_switch_event(struct trace_switch_event *switch_event,
                die("hm, delta: %Ld < 0 ?\n", delta);
 
 
-       sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
-                                             switch_event);
-       sched_in = threads__findnew_from_ctx(switch_event->next_pid,
-                                            switch_event);
+       sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
+       sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
 
        out_events = thread_atoms_search(&atom_root, sched_out, &cmp_pid);
        if (!out_events) {
@@ -1158,7 +1126,7 @@ latency_wakeup_event(struct trace_wakeup_event *wakeup_event,
        if (!wakeup_event->success)
                return;
 
-       wakee = threads__findnew_from_wakeup(wakeup_event);
+       wakee = threads__findnew(wakeup_event->pid, &threads, &last_match);
        atoms = thread_atoms_search(&atom_root, wakee, &cmp_pid);
        if (!atoms) {
                thread_atoms_insert(wakee);
@@ -1418,10 +1386,8 @@ map_switch_event(struct trace_switch_event *switch_event,
                die("hm, delta: %Ld < 0 ?\n", delta);
 
 
-       sched_out = threads__findnew_from_ctx(switch_event->prev_pid,
-                                             switch_event);
-       sched_in = threads__findnew_from_ctx(switch_event->next_pid,
-                                            switch_event);
+       sched_out = threads__findnew(switch_event->prev_pid, &threads, &last_match);
+       sched_in = threads__findnew(switch_event->next_pid, &threads, &last_match);
 
        curr_thread[this_cpu] = sched_in;
 

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 8bd5ca2d2f287e64a07e930ee15241ebb2e8664e..3b56aebb1f4bfab84b906c795fb4c91dc0bde886 100644 (file)
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -6,17 +6,15 @@
 #include "util.h"
 #include "debug.h"
 
-static struct thread *thread__new(pid_t pid, int set_comm)
+static struct thread *thread__new(pid_t pid)
 {
        struct thread *self = calloc(1, sizeof(*self));
 
        if (self != NULL) {
                self->pid = pid;
-               if (set_comm) {
-                       self->comm = malloc(32);
-                       if (self->comm)
-                               snprintf(self->comm, 32, ":%d", self->pid);
-               }
+               self->comm = malloc(32);
+               if (self->comm)
+                       snprintf(self->comm, 32, ":%d", self->pid);
                self->maps = RB_ROOT;
                INIT_LIST_HEAD(&self->removed_maps);
        }
@@ -52,10 +50,8 @@ static size_t thread__fprintf(struct thread *self, FILE *fp)
        return ret;
 }
 
-static struct thread *
-__threads__findnew(pid_t pid, struct rb_root *threads,
-                  struct thread **last_match,
-                  int set_comm)
+struct thread *
+threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
 {
        struct rb_node **p = &threads->rb_node;
        struct rb_node *parent = NULL;
@@ -84,8 +80,7 @@ __threads__findnew(pid_t pid, struct rb_root *threads,
                        p = &(*p)->rb_right;
        }
 
-       th = thread__new(pid, set_comm);
-
+       th = thread__new(pid);
        if (th != NULL) {
                rb_link_node(&th->rb_node, parent, p);
                rb_insert_color(&th->rb_node, threads);
@@ -95,19 +90,6 @@ __threads__findnew(pid_t pid, struct rb_root *threads,
        return th;
 }
 
-struct thread *
-threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match)
-{
-       return __threads__findnew(pid, threads, last_match, 1);
-}
-
-struct thread *
-threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
-                       struct thread **last_match)
-{
-       return __threads__findnew(pid, threads, last_match, 0);
-}
-
 struct thread *
 register_idle_thread(struct rb_root *threads, struct thread **last_match)
 {

diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 75bc843950c4a5df37e6c0dc38b50d4f41a413c7..845d9b62f96f9d65c9a687dc8c5c89dbc1157d1b 100644 (file)
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -18,9 +18,6 @@ int thread__set_comm(struct thread *self, const char *comm);
 struct thread *
 threads__findnew(pid_t pid, struct rb_root *threads, struct thread **last_match);
 struct thread *
-threads__findnew_nocomm(pid_t pid, struct rb_root *threads,
-                       struct thread **last_match);
-struct thread *
 register_idle_thread(struct rb_root *threads, struct thread **last_match);
 void thread__insert_map(struct thread *self, struct map *map);
 int thread__fork(struct thread *self, struct thread *parent);